DESCRIPTION(adapted from applicant's abstract): We request support for a symposium to be held on June 2-4, 2000 at Carnegie Mellon University, Pittsburgh, on the topic of Perceptual Organization in Vision. The aim of the symposium is to being together researchers from a variety of disciplines to consider mechanisms of visuoperceptual organization. Both behavioral and neural approaches will be considered. Behavioral approaches will include those arising from research in cognitive psychology, developmental psychology, and animal behavior studies. Neural approaches will include evidence obtained from single neuron recording studies, from neuropsychological studies of patients with discrete lesions to the cortical visual system and from functional neuroimaging studies. Quantitative and computational approaches will also be incorporated. The plan is to hold a three-day symposium with approximately a dozen speakers and an expected audience of 150-200 attendees. The following types of questions will be examined in the course of the workshop: 1) What are the heuristics involved in visual perceptual organization? 2) Are these predetermined and/or are they experience-dependent? 3) Do they operate only feedforward or is the system interactive, combining bottom-up and top-down knowledge in deriving organizational structure? 4) Do they operate early or late or are they perhaps more parallel than sequential? 5) What is an object? 6) What is the role of attention in perceptual organization? 7) What specific neural mechanisms mediate perceptual organization? 8) Is there potential for rehabilitation of individuals with deficits in perceptual organization? The general goals of the meeting will be to review the current state of the field from a multidisciplinary perspective by bringing together researchers who might not ordinarily exchange ideas, to provide the opportunity for junior scientists to be brought up-to-date and to interact with the speakers, to identify future research directions, and to disseminate the results broadly. Participants will include established researchers as well as promising new investigators. A dozen of the leading researchers in the field will describe their own research on issues such as grouping principles, figure-ground organization,amodal completion, surface derivation, object superiority effects, and the role of attention in organization. The new investigators and students will be given the opportunity to interact with the speakers in less formal settings as well as in question-and-answer sessions held throughout the symposium. Discussants and the keynote speaker will introduce historical perspectives and will provide a critical as well as synthetic viewpoint with the intention of delineating the existing gaps in the field. The results of the symposium would be published as the 31st in the Carnegie Cognition Symposium volumes pursuant to the standing contract for such publications with Lawrence Erlbaum Associates.